Synthesis and characterisation of temperature responsive poly (2-ethyl-2-oxazolines

Abstract

A bifunctional Poly(2-ethyl-2-oxazolines) containing hydrophobic end groups at both end of the polymer chains were synthesised by terminating a living cationic polymerisation with 4- bromomethyl benzoic acid. The results obtained for the clouding point measurement using UVvisible
spectrophotometer shows that bifunctional polymer containing 20 monomer units (DP 20) exhibited a lower critical solution temperature (LCST) near 49oC due to formation of hydrophobic domains by the polymer end-groups. In contrast, the polymer with 50 monomer units does not exhibit any LCST between 20 to 70oC due to the imbalance in the hydrophilic-hydrophobic interaction in this polymer.